Photo by D. Sillman
I hadn’t seen (or heard) a robin (good old Turdus migratorius) in several weeks. Over the early weeks of the Fall small flocks had passed over our hilltop on their south and west trajectories. Every once and a while one or two had dropped down from their flight paths and paused here in Apollo to snack on some local earthworms or grab some wild grapes, but there had been no robins for quite a while. It was exciting, then, last Saturday morning when I went out early to fill the front yard bird feeders and was greeted by a loud, unmistakably “robin” extended cackle. It took me several minutes to find the singer: it was a dark black robin with a bright red breast perched up on the almost leafless branches of my red maple tree. A Newfoundland robin!!
Robins spend their springs and summers as mated pairs with very loose flock connections. In the fall and winter, though, they form large flocks that travel locally from one feeding area to another. Many of these flocks even migrate long distances to spend the winter in milder, southern climes. The driving force that moves these flocks is food. In the late summer robins “disappear” from many places here in Western Pennsylvania much to the concern of local bird watchers. These “gone robins,” though, have just vacated one spot to concentrate themselves in some other locale that has more abundant food supplies. People living in these robin-blessed sites wonder at the population explosion going on around them and are concerned by the out-of-control expressions of nature. Deborah and I were driving out in Burrell Township (Armstrong County, PA) late one July a few years ago and were stunned by the thousands and thousands of robins that were hopping around on the ground and perching on almost every free tree branch. The noise they made and the mess they created on every surface with their droppings (is this where their genus name comes from?) were astounding!
It is interesting that although the American robin is one of the most common, most abundant, and most recognized birds in North America its migration patterns are not at all well described. I think that the lack of patterns in their year to year migrations at the onset of winter and then at the advent of spring is due to their dependence not on temperature or weather patterns or geomagnetic sensory systems (things that would be predictable and generate fairly hardwired responses) but instead it is because they follow their food supplies wherever the vagaries of the previous season generate scattered spots of abundance.
American robins are found all over North America. They summer and breed in Canada and Alaska, spend the entire year and breed all across the continental United States, and winter down to southern Mexico and even just a little further south into Central America. The mid-February “arrival” of the robins here in Western Pennsylvania is major sign of spring but probably represents just the ebb and flow of locally overwintering populations transiently leaving their sheltered (and probably fruit filled!) hollows and valleys on short forays out into suburban landscapes to look for earthworms in thawing acres of yard grasses.
I am familiar with three of the seven subspecies of T. migratorius. The subspecies here in Western Pennsylvania is the classic (or “nominative”) form of the American robin. It is widely distributed across the northern United States and Canada all the way north to the very edge of the tundra. The “Newfoundland” subspecies (whom I think that I saw up in my tree last Saturday) has darker black back feathers and redder breast feathers than its nominative subspecies. It may also be (in my opinion anyway, although I could find no reference that agrees with this!) slightly larger than our “usual,” nominative robin. These “Newfoundland” robins may simply represent a color form that is out on one extreme of the species normal color distribution. “Black backed” robins can be seen almost any time of year through the bird’s North American distribution. But this dark, intense coloration does seem to predominate in the robins from Canada’s northeastern coast. The third subspecies is the “Oklahoma” robin. This robin’s back feathers are more gray than black, and it has a pale, reddish orange breast. They look dusty and dry (as is fitting the dust-bowl center of their distribution). When I visited my parents in Tulsa these are the robins I would watch ranging across the suburban lawn-scape as they searched in the coarse grasses for worms.
Photo by David Hoffman (Flickr)
Changing the subject to snakes! My good friend Carl Meyerhuber called me last weekend to report a sighting down on the Roaring Run Trail. Near the Canal Street parking lot Carl spotted an immature ring-necked snake crawling slowly across the trail. It seems very late (and it has been very cold!) for these delicate snakes to be out and about. It was a good thing that Carl was there to make sure that this slowly crawling, well chilled young snake made it all the way across the trail! Last summer I wrote about ring-necked snakes and said that in spite of the DER’s declaration that they are one of the five most common snakes in Pennsylvania I had never seen one. They are shy and nocturnal and hard to find. I hope that this little immature ring-neck found a suitable place to hibernate down in the vegetation beside the Kiski River. I will look around for him next summer!